Integrated circuits include many electronic components connected in various ways. A field effect transistor (FET) is a type of electrical component having a source, a drain, a gate, and associated electrical contacts. In many embodiments, the surface of the transistor is silicided prior to forming an electrical contact as the silicided surface is very conductive and improves the electrical connection at the transistor. As integrated circuits become smaller, the area of the silicided surface becomes smaller, so the integrity and quality of the silicided surface becomes more important.
Resistors are required in many electrical circuits for various purposes, e.g. as voltage dividers or as fuse resistors. The resistors are designed and built for a particular resistance, and proper operation of the electrical circuit depends on the expected target resistance and specifications for the resistor being fulfilled. Several types of resistors are common in integrated circuits, such as silicided resistors that have a lower resistivity and non-silicided resistors with a higher resistivity. Therefore, non-silicided resistors are typically protected while the contact locations on the transistors are silicided. This can involve covering both the transistors and the resistors with various layers, which are typically dielectric materials, and then removing the layers over the transistor for the siliciding process. However, transistors are being placed closer and closer together to develop smaller and smaller integrated circuits, and this creates smaller gaps between the gates of adjacent transistors. As the gates are placed closer together, it is becoming more difficult to remove all of the dielectric material between adjacent gates, especially when the covering layers are so thick that they can merge in the space between adjacent transistor gates. This can result in incomplete removal of the dielectric layer between the gates, which produces dielectric residuals on surfaces of the transistor. The dielectric residuals can interfere with the siliciding process, which in turn interferes with the electrical connection between the transistor and other electrical components. Increasing the etching process to remove the dielectric residuals results in undesirable, excessive etching on other components of the integrated circuit.
Accordingly, it is desirable to develop new systems and methods for protecting resistors while transistors are silicided. In addition, it is desirable to develop new integrated circuits with thin protective layers over the resistors. It is also desirable to develop systems and methods to lower the likelihood of dielectric residuals on transistors prior to siliciding the transistor contact locations. Furthermore, other desirable features and characteristics of the present embodiment will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.